Rotary vane pump

ABSTRACT

A ROTARY SLIDING VANE PUMP IN WHICH THE VANE SPRINGS ARE POSITIONED IN THE WORKING CHAMBERS AND ENGAGE RECESSES IN THE SIDES OF THE VANES TO PRESS THE VANES OUTWARD AGAINST THE CAM PLATE.

Sept. 20, 1971 os 3,606,605

ROTARY VANE PUMP Filed Jan. 15, 1970 5 Sheets-Sheet 3 Inventor F/v'tz 03f wa/d Agent 3,606,605 ROTARY VANE PUMP Fritz Ostwald, Buchschlag, Germany, assignor to International Telephone and Telegraph Corporation, New York, N.Y.

Filed Jan. 15, 1970, Ser. No. 3,135 Int. Cl. Flc 1/00; F04c 1/00, 15/00 US. Cl. 418-253 6 Claims ABSTRACT OF THE DISCLOSURE A rotary sliding vane pump in which the vane springs are positioned in the working chambers and engage recesses in the sides of the vanes to press the vanes outward against the cam plate.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to rotary sliding vane pumps and particularly to pumps of this type having springs for pressing the vanes outward against the cam wall.

Description of prior art In order to eliminate elastic deformations of the rotor segments or breaking of the segments under the influence of the hydraulic force exerted on the vanes of a rotary sliding vane pump, the trend is to design the vanes and the guide slots in the rotor as thin as possible to increase the strength of the segments. However, this increases the difficulty in designing springs for pressing the vanes against the cam plate curve and the use of coil springs acting against the bottom of the vanes is not practical with the thinner vanes.

To meet these requirements, a known vane-type machine has vanes which are pressed against the cam plate by means of a bracket-like fastening spring arranged on the side of the rotor. The ends of the bracket spring are propped against two vanes located at an angle of 90 to each other and the loop in the center of the spring is wound around a bolt fixed in the rotor. The pump is designed so that when the vane at one end of the spring is being pushed into its slot by the cam surface the vane at the other end of the spring is sliding outward in its slot. Thus the bracket spring acts like a two-armed lever which is resilient to compensate for the tolerance.

A disadvantage of this arrangement is that the spring is arranged on the side of the rotor and the rotor can be pressed against the side wall only in a narrow area in the peripheral region of the rotor thereby causing a sealing problem. Further, the guide slots of the vanes communicate with one another through the cavity between the rotor and the side wall so that they can only be pressurized jointly. But in the pressure-controlled vane type machines which are common today it is necessary to vary the pressure continuously in the individual vane slots. A vane-type machine of the kind in which a controlled pressure acting against the bottom of the vane stem assists the spring in pressing the vane against the cam plate could not be obtained with the above-mentioned construction.

A further disadvantage of this bracket spring arrangement is that an even number of vanes must be provided at suitable angular spacing between vanes. Also, the vanes may have a tendency to tilt in their guide slots.

In pumps having vanes thick enough to have holes in the bottoms of the vanes for retaining coil springs, the

3,606,605 Patented Sept. 20, 1971 thickness of the vanes reduces the strength of the rotor segments between the vanes. The thick vanes also have a large absorption and displacement volume causing considerable quantities of pressure medium to flow through the control of the holes in the vane stem, thus unfavorably influencing the pressure ratio between the working chamber and the space under the vane stem and necessitating a stiffer spring.

Moreover, in order to assure easy sliding in the vane slot, a certain limiting value of the ratio of vane thickness to guiding length must not be exceeded.

SUMMARY OF THE INVENTION An object of this invention is to provide a rotary sliding vane compressor with springs for pressing the vanes outwardly against the cam plate in which the vanes are relatively thin and there are no leakage paths through the spring chamber.

This object is achieved by providing springs which are arranged in the working chambers between the vanes and which have ends engaging notches in the parts of the vanes forming the working chambers.

The fastening springs may have a central loop wound around a fixed holder to obtain the necessary initial stress, or the springs may have central loops which rest in recesses in the rotor.

The vanes may be T shaped with the ends of the springs acting on the bottom of the cross section of the vane or they may simply have notches in the face of the vane into which the ends of springs fit.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic partial sectional view of one embodiment of this invention.

FIG. 2 is an exploded perspective view showing the assembly of the springs and retainers of FIG. 1.

FIG. 3 is a partial sectional view of another embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 and 2, there is shown a rotor 1 having radially extending guide slots 26 with chambers 6 at the bottom of the slots. Sealing vanes 5 are slidably mounted in the slots and the outer ends of the vanes contact a cam plate surface 10. A recess 2 is formed in the outer perimeter of the rotor leaving edges 3 to seal the working chamber 4 between the vanes. Pins 7 extend across the working chambers and are supported by holes in the edges 3. Springs 8 having at least one central loop are held in the recess by the pins 7 and have r ends which engage lateral recesses or grooves 9 in the sides of the vanes. Since there is no connection between the chambers 6 and the recess 2, the pressure in the chambers 6 may be controlled independently.

Although springs are shown engaging both sides of each vane, it will be apparent that half that number of springs could be used with only one side of each vane engaging a spring.

FIG. 3 shows a second embodiment which is similar to that shown in FIGS. 1 and 2. In this embodiment the vanes 21 are T-shaped while loops in the center of the springs 22 rest in recesses 23 in the rotor surface 24. As in FIGS. 1 and 2, the springs 22 press the vanes 21 against the cam plate 25.

It will be appreciated that the invention illustrated and described herein may be modified by those skilled in the art without deviating from the spirit and scope of the invention as set forth in the following claims.

I claim as my invention:

1. A sliding vane rotary machine comprising:

a cam plate;

a rotor disposed in working association with said cam plate, said rotor including guide slots disposed radially therein and two parallel edges extending radially from the peripheral surface of said rotor toward said cam plate but spaced therefrom;

a plurality of vanes each disposed in one of said guide slots and extending outwardly therefrom for engagement with said cam plate, a portion of adjacent ones of said vanes, said edges of said rotor and said peripheral surface of said rotor forming a working chamber; and

at least one spring disposed in said working chamber engaging said portion of adjacent ones of said vanes to force said vanes outward against said cam plate.

2. A machine according to claim 1, wherein:

each of said vanes include a recess in the face of said portion, and

said spring includes a central coil and arms extending in opposite directions from said central coil to engage said recess of said adjacent ones of said vanes.

3. A machine according to claim 2, further including a pin extending through said central coil and said edges to anchor said spring.

4. Amachine according to claim 1, wherein each of said vanes include a stem extending from said working chamber into the associated one of said 2 guide slots and a cross piece connected to said stem and engaging said cam plate, said stem and said cross piece forming a T shaped cross section, and

said spring includes a central coil and arms extending in opposite directions from said central coil to engage the bottom of said cross piece of adjacent ones of said vanes.

5. A machine according to claim 4, further including a pin extending through said central coil and said edges to anchor said spring.

6. A machine according to claim 5, wherein said peripheral surface of said rotor includes a recess therein within said Working chambers, and

said central coil is anchored in said recess of said peripheral surface of said rotor by said pin.

References Cited UNITED STATES PATENTS 138,744 5/1873 Elsaesser 4l8258 616,766 12/1898 Bruce 418266 2,082,265 6/1937 Smith 418-258 2,641,194 6/1953 Jones et al 418258 2,778,317 1/1957 Cockburn 418266 3,183,843 5/ 1965 Cockburn 418--266 CARLTON R. CROYLE, Primary Examiner J. J. VRABLIK, Assistant Examiner US. Cl. X.R. 

